[Telangiectatic osteosarcoma secondary to a liposclerosing myxofibrous tumor: a case report].

Malignant transformation of a fibrous dysplasia into an osteosarcoma is very rare. We report the case of an 84-year-old man with telangiectatic osteosarcoma of the upper femur arising in a previous fibrous dysplasia also known as liposclerosing myxofibrous tumor. The tumor was expressing the epithelial membrane antigen. This is the first described case of a malignant transformation into an osteosarcoma arising in a liposclerosing myxofibrous tumor. We discuss the main differential diagnosis with a review.